package com.kaifamiao.www.demo.Do29.am;

public class Demo {
    public static void main(String[] args) {

        Pet pet = new Pet();
        pet.say();
        call(new Pet());
        call(new Dog());
        call(new Cat());
        call(new Pig());
    }
    public static void call(Pet pet){
        pet.say();
    }
}
